The present invention relates in general to magnetic linear drives of the type which include an armature supported for reciprocating movement within a tubular member and activated by means of a solenoid coil radially arranged on the tubular member to induce magnetic flux in the armature. Such magnetic drives are used particularly in connection with sliders of valves.
The disadvantage of prior-art magnetic drives of this kind is the fact that a relatively large current is necessary for energizing the armature and its force acts in a single direction only (proportional magnet).